


divide and conquer

by armethaumaturgy



Series: Reqs [8]
Category: Undertale (Video Game)
Genre: Blood Loss, Blood and Gore, Blood and Injury, Blood and Violence, Canon-Typical Violence, Cross (X-tale) - Freeform, Dismemberment, Dust (Dusttale) - Freeform, Horror (Horrortale) - Freeform, Illustrations, Killer (Killertale) - Freeform, M/M, Near Death Experiences, Nightmare (Dreamtale) - Freeform, Poisoning, bad sans poly - Freeform, how many blood-related tags can i put on this to make sure i dont throw people off-guard??, star sanses
Language: English
Status: Completed
Published: 2021-03-08
Updated: 2021-03-08
Packaged: 2021-03-15 04:22:11
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,751
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29927850
Author URL: https://archiveofourown.org/users/armethaumaturgy/pseuds/armethaumaturgy
Summary: They’d expected the Stars to split, just like they had.And, just because he’d thought it was goingfine,he’d jinxed it.
Relationships: Sans/Sans (Undertale)
Series: Reqs [8]
Series URL: https://archiveofourown.org/series/2151672
Comments: 9
Kudos: 84





	divide and conquer

**Author's Note:**

  * For [zephyred](https://archiveofourown.org/users/zephyred/gifts).



> this was written for @xxlucidry on twitter! and the illustration is yet again by my lovely wife, @reclawedcat on twitter♥♥
> 
> please heed the warning and tags!!

Dream was a bitch to fight.

Horror hated how it was almost always him who was stuck with the little yellow menace, but it made sense, he supposed.

Dream was primarily ranged, and the more they kept him from using his bow, the better. He also wasn’t as good with his little daggers —  _ yet,  _ a small part of Horror’s mind reminded him — so it gave him another advantage, aside from his reach being longer.

Dust was a little way off holding Blue back; he was great at corralling, and despite his own preference for staying out of the thick of it, he was doing infinitely better holding his own against Blue’s hammer than Dream was with him.

Cross had his own hands full with Ink and the purple paint he tried to hold him down with.

The assessment took maybe half a second, just long enough for Horror to swing his axe in a wide arc. He caught Dream in the humerus, tearing through the fabric of his long glove and spraying marrow all over the snowy ground. He was glad to know things were going their way, despite the unexpectedness of all three of the Stars confronting them.

They’d expected them to split, just like they had.

And, just because he’d thought it was going  _ fine, _ he’d jinxed it.

Dream cried out, dropping one of his daggers in favor of cradling his arm, but the cry was echoed from off in the distance.

Horror’s head whipped towards the sound, and it felt like time slowed down as his eye widened. Dust must have miscalculated his bone pattern, because Blue got close to him. Close enough to hit him and then take a swing, the hammer mimicking the wide arc Horror’s axe had taken moments ago.

And then it connected.

Dust didn’t move away, not fast enough, and the entire side of the giant hammer came down upon his torso.

The sound of glass shattering and bone breaking registered after Dust’s mouth opened in a soundless scream that also only became audible seconds after it began.

Time sped up again, and Horror was powerless to do anything as Dust went flying backwards, hitting one of the trees with another sickening crunch. He made a pathetic sound from where he ended up slumped on the ground, crimson staining the front of his shirt and hood, but Horror could spot something else, as well.

Horror turned just in time to catch the blade of Dream’s dagger with the handle of his axe, metal digging into the wood. Horror growled deep in his throat, pushing back. His axe creaked, but she was sturdy, and Dream went back laughably easy.

“Fuck!” Dust shouted, grabbing his attention again. He was struggling against Ink’s purple chains, pinning one of his arms to the trunk of the tree. There were glass shards all around him, half-broken vials of his poisons spilled…

All over him.

“Looking for this?” Ink asked, leaning down to pick up a vial that looked miraculously intact, even as he dodged Cross’ knives flying at him. He held it up to the light like a new toy, peering at the off-yellow, opaque liquid inside.

Dust reached out towards him, yanking at the chains and raising a line of bones, but not before a shadow befell both of them.

Horror moved, but he didn’t make it a step before Blue came from above, hammer held tight as momentum propelled him downwards. There were more sickening crunches, and this time, Dust’s scream rang in his acoustic meatuses the moment it tore itself out of him.

The arm he’d outstretched towards Ink was now pinned to the ground under the flat edge of Blue’s hammer, his other arm twisted unnaturally in the chains as his whole body got forced to the ground. He was staring at the point where the hammer met the ground with wide sockets, eyelights nothing but tiny pinpricks in a sea of black.

Crimson and lilac stained the snow, spattered from around the hammer and mixing with ashen dust, and yet all Horror saw was  _ red. _

His eye zeroed in on Blue, who looked equally shocked by what had just transpired, and growled low in his throat. “You’ll pay for that!” he cried, Dream forgotten as he charged straight for the fucker who dared hurt his mate.

“Don’t even think about it,” Cross hissed, and for a microsecond, Horror thought he was being stopped, and was ready to all but bite Cross’ head off. But no, he was stopping Dream from following, or taking a cheap shot when his back was turned.

With every step he took towards the blue-clad runt, the air around them got colder and heavier.

**“What happened here?”**

Nightmare’s voice was loud and piercing, but not even it could stop Horror in his tracks. A pair of tentacles and a blur of red and blue moved in his peripheral vision, and yet Cross was somehow faster than him, by Dust’s side in the blink of an eye.

He pulled Dust up, hacking away at the chain while holding him as still as possible. There was a veritable puddle of marrow and magic under him by now. 

Another pair of tentacles curled around Ink’s body, squeezing him so tight the creaking of his bones was audible, and he let go of the vial. After a moment or two of struggling, followed by a heavy  _ snap _ of some bone breaking _ , _ his body went lax in Nightmare’s hold.

Cross looked up from Dust, and there was a blazing inferno behind his eyelights.

“Get him,” he hissed, tone so unlike what he usually sounded like that Horror could taste his rage, mirrored in the hard line of his browbones as he cradled Dust close to himself. 

Blue’s hold on his hammer was shaky, even as he held it up.

“How… dare you,” Horror said, voice gravelly as it came from the depths of his throat. Blue held his weapon before him, eyelights flicking between Dust and Cross — who had started healing Dust’s slumping body — on his right, and the way Horror lifted his axe in front of him.

The weapons met with a deafening  _ clang, _ but the warhammer was not made for defense.

Blue struggled to angle it to meet each swipe of Horror’s arm. It wasn’t a fight.

Horror was stronger than Blue even in the best of shapes, and he  _ wasn’t _ in the best of shapes. Fighting Dust was no easy ordeal. Off from the side, Nightmare’s tentacles slithered in and wrapped around Blue’s ankles, throwing him off kilter.

It was the perfect opportunity, and Horror’s axe lodged itself straight through Blue’s clavicle, all the way to his scapula. It pulled a cry from the Swap, but it didn’t sound like  _ enough. _

As he stood up, foot stomping onto the handle to drive it further, he realized the entire area was covered in darkness, moving like an entity unto itself. A veritable mass of tentacles sprouted from Nightmare’s back, sliding over one another as they covered the forest around them.

“Nightmare!” Dream called over the loud noises of his daggers meeting the cold steel of Killer’s knives.

Horror stooped down and wretched his weapon out of Blue’s shoulder, along with another spattering of marrow and a cry that was a bit closer to what he wanted, to what  _ Dust  _ had sounded like.

“Night!”

Cross and Dust were both bathed in a green light, stark against the darkness surrounding them all, and Horror didn’t like the tone of Cross’ voice. His foot returned, this time colliding with Blue’s wound, and grinding the broken bones into little more than dust.

“I can’t heal him!”

Horror didn’t know how long he stayed like that, pulling cry and cry out of Blue, reveling in the cyan tears cascading over his cheekbones. He’d caught sight of lilac on Dust’s face, so it was only  _ fair— _

“Enough,” Nightmare called, and all Horror could feel over the acidic cocktail of worry and anger swirling over his SOUL was disappointment. “We have to heal him properly!”

He stepped away from Blue — or whatever was left of him, crying and trembling in a curled up, bloody ball — and allowed himself to be led by one of Nightmare’s tentacles towards the portal awaiting them.

He felt like he was in a haze as they all rushed back and forth, Nightmare laying Dust onto the couch as gently as physically possible, apparently having taken him from Cross at one point. The smell of marrow became cloying and Horror realized he was drenched in it. He could smell it with each breath he took too fast, taste it on the back of his palate. He felt gross and after the anger melted off into something that didn’t feel like it was swallowing him wholly, all he was left with was panic, staring down at Dust’s shivering body.

_ Holy shit, _ he realized, with a feeling of his SOUL sinking to the bottom of his ribcage.

Dust’s left arm was gone.

Horror’s whole body froze, as if all the marrow in his bones turned to ice in an instant.

Killer was gripping the vial Dust’d lost it for, uncorking it with shaky fingers and tipping the contents into his slack mouth. He coughed on it weakly, shaking like a leaf as he bled lilac magic all over the living room.

Nightmare settled on the floor, next to the couch, and lifted Dust’s shirt to reveal the damage done by Blue’s first swing.

Horror felt like he was going to puke. Dust’s sternum was shattered with spiderweb cracks, barely holding together with weaker, fresh pieces of bone that only existed thanks to Cross’ healing. There were chunks of his ribs missing, rattling around at the bottom of his ribcage with his labored, shaky breathing.

“Horror, hold him,” Nightmare said, snapping him out of his horrification. He scrambled to comply, hesitating as to where to put his hands to cause as little damage as possible when he noticed Dust was awake, and staring at him with faint, tiny pinpricks of eyelights. “Killer, get the first aid kit.”

“On it.” Killer gone before he’d even finished his words.

“I’m—I’m fine,” he said, and Horror supposed he was trying to reassure him — all of them — but his voice was barely a hoarse whisper and there were lilac tears at the corners of his sockets, rolling down his cheekbones, and there was magic _ pouring _ out of his shoulder—

“Don’t speak,” Nightmare chided as Horror’s hands found themselves on the shoulders, so he couldn’t hurt himself with his shaking. He put as much pressure as he could onto the broken leyline, but he could still feel thick, viscous magic slipping between his phalanges. “Cross, I need you to—”

“Yeah.”

Cross rounded the couch and leaned over, green light befalling them and Nightmare reached into the broken mess of a ribcage and started scooping out the broken shards of the ribs. As he pulled them out to see what was what, Horror was reminded of a grotesque version of a jigsaw puzzle.

Dust seemed to be coming around to himself, for better or (definitely) for worse, breath stuttering as Nightmare held the shards in place, Cross’ magic slowly knitting them together, one by painful one. By then, Killer had returned, and in his hands was a jar of the healing gel they usually used.

He started lathering it into the pieces Cross knit back together, the gel’s fainter glow getting lost under Cross’. He was sweating, face set in a focused scowl. It was an ordeal and a half to get Dust’s ribcage to look like something that  _ resembled  _ a ribcage again, and by the tail end of it, Horror could barely hold him down as he twitched, writhing with pained yelps and sobs falling from him with every choked breath.

“Night,” Cross said, voice choked, “He’s losing too much magic!”

Nightmare grit his teeth. He knew that. Dust’s HP was still ticking down, though slower than it had been; the antidote must’ve taken effect on whatever poisons had gotten into the exposed wounds.

“Night!”

“Fuck,” he hissed back, “I know! I know.”

His tentacles curled around them all, all but cocooning Dust in their hold as he teleported them into the infirmary.

The room smelled stale, faintly medical and sterile from the cabinets lining the walls. They hadn’t used it in a long time, any and all injuries treated in someone’s bedroom or the living room. It had been nothing but a half-forgotten relic of past years, when it had been repurposed into one, back when they were more careless, less accustomed to fighting together, to keeping an eyesocket on each other’s backs.

Nightmare wouldn’t have minded if that had been all it’d stayed as. One of his tentacles flicked the overhead lights on, loud and buzzing and entirely too bright. The surgically white glow revealed the full extent of the damage to his arm as Nightmare tried to keep Dust’s shivering body as still as he could.

Marrow, he was used to. Marrow, he could handle.

But he was — they all were — soaked in Dust’s leaking magic, as well, and  _ that  _ scared him.

Killer yanked the cover off one of the three cots they had sitting in the room and Nightmare placed Dust onto it. And immediately wrapped his tentacles around him again, to stop him from throwing himself straight to the floor.

A blood-curdling scream tore itself out of Dust’s throat, bouncing between the walls like it wanted to etch itself into them, deep as they went.

Everyone flinched, and it was just Nightmare’s voice, yelling over the sound, that snapped them out of their terror.  _ “Hold him!” _

Horror and Killer moved to grab a leg each, and Nightmare’s tentacles wretched Dust’s arm away from him, all but pinning it down to the cot.

Cross circled them all to the other side, hands shaking even as they glowed a bright shade of green, pouring healing magic into him once more, trying his hardest to mend the broken leyline that had started bleeding more lilac without Horror’s hand to stem the flow.

While Nightmare’s own body felt taut, adrenaline so heavy in his bones it took real restraint to keep his tentacles still and tight, Dust looked like the pain was gaining an upper hand over him. Even with all of them holding him down, they weren’t able to keep him  _ still. _ His spine arched at a painful angle off the cot; one tentacle moved to hold it down, but it wasn’t  _ enough. _ With each pulse of Cross’ magic, a scream clawed its way out of Dust.

“It’s not working!” Cross cried, tears rimming his eyesockets and he desperately pushed more magic into the leaking wound, even if it was obvious he was running out. There was a growing puddle of lilac spreading under all their feet. Dust’s HP kept dropping. Cross was panicking.

They all were. Nightmare could taste it in the air, acrid and sour, all the fear and rage and concern.

Dust’s voice broke on one of the cries, devolving into a mere, pitiful whimper. Nightmare felt it touch something in the depths of his corrupted SOUL.

“Move!” he ordered Cross, who took a moment too long to respond to a command he already would have under normal circumstances, so he simply shoved him out of the way.

He took every last ounce of their emotions, every scrap of marrow-deep fear, every bit of their hate towards the Star Sanses, every shred of concern running through them, and let it all fill him.

The negativity on his bones roiled, thick and heavy in its sluggish movements, when he forced his magic to do something it hadn’t for centuries.

His healing magic was darker, a grassy, dull shade of green that was unmistakably  _ wrong  _ to everyone, but it poured out of him nonetheless, crackling when it came into contact with Dust’s leaking lilac, and the body on the cot seized up, empty sockets wide as they stared, unseeing, at the ceiling.

Exhaustion pulled heavy on his limbs, sweat beading on his skull from the unfamiliar strain, but Nightmare didn’t let up until the lilac stopped  _ gushing, _ the open leyline tentatively closing under all the intent he could embed into his magic.

Dust’s thrashing died down to full-body shivering, but even so, it still proved hard to hold him down, to keep him from reopening the barely mended wound.

Delirious, Dust’s skull lolled down to his chest, eyelights flickering as they tried to manifest. When they managed to, they were glossy, fuzzy around the edges, and it would have been a miracle if he could see anything with them. He stared down at himself, almost every inch of his body coated in his magic, and his stare was blank, only marred by the grimace whenever a pulse of pain wracked him.

And then he inhaled, shakily. It turned into a breathless chuckle, and then into choked laughter, wet and making his ribcage rattle.

He raised his gaze to Nightmare, but it didn’t look as if he could really _ see _ him. He gasped. “I—I’m… turning into _ dust,” _ he babbled, words slurring together. All the screaming he’d done wasn’t doing his voice any favors, and he sounded like he’d swallowed a cheese grater. “That’s  _ hilarious!  _ ‘Cuz I’m… I’m Dust… and I’m—I’m turning to dust…”

Killer inhaled sharply, watching him with terrified sockets. His SOUL was wavering around the edges, shape wobbly. “Shut up! You’re not fucking dusting!”

Dust’s head lolled in his direction, staring right through him. “Why… aren’t you laughing It’s— that’s hilarious!” There was desperation in the words, sobs overtaking his bouts of laughter. There were still fat, purple tears rolling down his skull, mixing with all the other magic he’d lost.

Nightmare moved one of his tentacles off his shoulder, once he was sure the leyline wouldn’t burst open again. He moved it over Dust’s face, covering his sockets.

“Hush,” he said, and it was quiet and tentative and nothing like him.

Dust’s sockets fell shut under his touch with no further coaxing, the little bit of sleeping magic enough, along with his exhaustion, to knock him out.

He went still under them, and none of them were sure if it was better than the thrashing had been, or not.

They refused to leave Dust's side. Horror had taken to cleaning the marrow and the magic off of him with a wet rag, hands slightly trembling.

Cross had slumped into one of the chairs, Killer couldn't seem to stop pacing, and Nightmare just... stared. His SOUL was pounding in his ribcage, and even through the layer of corruption, it was a miracle and a half that no one else could hear its rapid  _ 'thump-thump.' _

Dust would startle in his slumber occasionally, jerking on the cot, and every time, Horror would let out a distressed, panicked sound that Nightmare was quickly growing hateful of. Not because of Horror himself, or the care and worry thick in the room, but... because of the circumstances. It took all of him not to leave right that second to hunt his stupid idiot of a brother down and repay the fun of the night to him with doubled interest.

Horror's show had not been enough.

"That..." Killer muttered, pausing in his idle pacing for the first time. He looked sickly with the coating of drying marrow and magic all over him, clothes matted together. He was looking down at Dust, at the faint glow of the exposed leyline in his shoulder, and he seemed almost scared, like it could start hemorrhaging at the drop of a pin. The dark hate rolling down his cheekbones was thin and watery, but Nightmare didn't mention the ratio of it compared to tears. "That ain't growing back, is it?"

Cross curled up on himself, hiding his face in his stained hands, and the tears he'd been holding at bay ran free with a sob. "I— I tried!" he cried, "I did everything... I-I'm so—"

"Hush," Nightmare stopped him, just as quiet as his voice had decided to be since Dust's outburst. Just thinking about leveling it made unease crawl up his spine. "You did good. He's alive."

Just barely, but he was.

He had dropped down to single digit HP.

While that wasn’t atypical for a Sans, Dust had enough HP to go into five digits. Seeing him so low… 

Cross kept weeping. One could barely tell, really, with the way his magic's color was so close to Dust's, lost in his own cover of gore.

"Go get cleaned," Nightmare told them, but all he got for his troubles was them scooting closer to the cot. He couldn't even be mad, because the idea of leaving Dust alone and vulnerable made his non-existent stomach protest, too. With a sigh, he amended, "One by one. It won't do to let him wake up and think he hurt us."

The idea of Dust awaking to see the entire room — and them, by extension — looking like a scene of… well. No one seemed to like that, either. Cross stood up, rubbing at his skull with more force than was necessary, and straightened out from his slouch, though it wasn’t his usual confidence. 

“I’ll go first. So Horror can… So I can keep watch when Horror does.”

Killer bit back a remark that was on the tip of his tongue —  _ he’s here. He won’t let anything happen to him.  _ He wondered if Nightmare could tell a part of his guilt was from not getting there in time. Wondered if their leader felt the same guilt.

Cross slipped out of the room, his footsteps echoing from beyond the door in the silence. Though if Killer strained, it almost felt like he could still hear the screams, as if they were still echoing. He shook his head.

“Scoot, big guy,” he told Horror, dropping into a chair next to him. He’d wiped off pretty much all the marrow and magic, inadvertently uncovering their shoddy job of patching up his ribcage. He’d need new clothes, too, but that was the least of their worries.

The pieces of ribs hung on by the stars’ will, so Killer took the roll of bandages Horror held, and started wrapping the ribcage up. Dust winced when he pulled the fabric tight, and unconsciously he muttered a quick, ‘sorry, buddy,’ even though he knew Dust couldn’t hear him. But he needed to make sure nothing would fall out of place, and his fingers fit into the intercostal spaces easier than Horror’s.

Horror stared as his hands as he worked, and Killer wasn’t Nightmare, couldn’t read emotions, but he knew what guilt looked etched into a browbone. His own probably looked the same.

“Hey,” he said, tying the end of the pristine bandage into a bow, a small thing right there over where Dust's SOUL fluttered weakly under the layers of them. His fingers glazed over the handiwork one more time, softly, like they weren't there at all. Horror had turned to look at him, inclining his head the barest amount to indicate he was listening. "How about y'cook up something for him, for when he gets up?"

Horror hummed. Killer was right, food would speed up the healing process, refill some of the HP Dust desperately lacked. But he still didn't want to move, didn't want to let go of the hand he'd taken to gripping. It felt cold in his own.

"He likes those roasted potatoes of yours," Killer continued, like he could read his train of thought. He looked up, the eyelight in his left socket faint, but piercing. "Go on, big guy. Won't let him get hurt again."

It was dangerously close to a promise, something neither of them liked, but Horror simply nodded. He still didn't let go of Dust, not for a few more moments, but Killer didn't fault him. If there was another hand— 

If he could've, Killer would've held the other one.

Eventually, Horror did let go, placing Dust's hand onto the cot by his side more gingerly than Killer had ever seen him do anything, and left. Now it was just him and Nightmare to keep Dust company.

"Do you—"

"No separating again," Nightmare said, cutting him off. He didn't move, but when one tentacle wound itself around Killer's midriff, he simply reached down and squeezed it.

"Not for a while, huh?" he mused, earning himself a shake of Nightmare's head. He understood. "He's gonna be fine, boss."

"He better be. You can—"

"I'll wait for Criss-cross to get back."

"Very well."

There was nothing to do but wait now. So they waited.

* * *

_ Crash. _

Dust winced at the sound of glass breaking, and he didn't need to look to know Cross had, too. Instead of seeing the momentary flash of panic on him, he gripped the edge of his desk, joints turning white at the grip.

Trying to do anything with his right hand was proving to be a nightmare, and he had half a mind to upturn the table whole and break the rest of the breakers.

"Do you want me to clean—?"

"Don't," he hissed, before Cross could finish his offer. His shoulder ached with a jolt of phantom pain; not only was he assigned a buddy for all waking — and non-waking — hours of the day, they were treating him like he was incompetent to boot. "Oh, shut up," he told Papyrus, not bothering to listen to his brother's tirade.

Unhooking his claws from the table one by one, he leaned down and started scooping the broken glass shards up. The beaker had only held a weak solution, prepared for the ground up herbs he had waiting, so he didn't even need to tell Cross to get out of the room. He wanted to, though, wanted a couple minutes to compose himself.

On instinct, he was trying to move his left hand, and the sensation of  _ knowing _ he was trying to move it didn't really connect with the fact that nothing did, in fact, move.

His magic flared at his emotions, scorching along the leyline that would never be functional again, and he could've cried. He wasn't going to, no need to give him the others  _ more _ reasons to pity him. At least his ribcage had stopped feeling like it was constantly on fire, even if the shoulder hadn't.

He winced at the next jolt of pain running through him, and tried to brace himself on the floorboards, yet again reminded of the fact that he couldn't. 

Except he felt more stable where he knelt, and looking down, his arm was back. Wait, that made no sense. Be blinked, bone turning into shining ecto-flesh, holding him upright.

It was a bit disproportional, wobbly with no inner structure to hold it, and Dust had to expend actual conscious effort to move it, but it was there nonetheless.

Cross was staring at him — at the arm — with wide sockets as if the thought of such a possibility hadn't occurred to him, either. Dust flexed the construct's claws, magic sizzling where it connected to his shoulder. It didn't feel like his own, not really, but it was better than nothing.

It was enough for the others to stop fussing about him.

* * *

Blue gripped his hammer, automatically moving to Dream's left flank. They were up against Nightmare's whole gang this time, and he could feel his hands shaking where they held the handle of his weapon.

Dream was talking to Nightmare, but Blue wasn't sure what either of them were actually saying. His gaze was trained to Dust, stepping out from behind Killer. He couldn't stop looking where both his sleeves were cut off, scapula on full display.

"Oh my gosh," he breathed out, without meaning to. "Are you— are you okay? I—I didn't mean to—"

Dust's eyelights flicked to him, nothing but two pinpricks, and Blue found himself yelping, breath knocked out of him as he was slammed into one the local Hotlands' buildings.

His hammer fell from his fingers and he was face to face with Dust and his hard glare.

Lilac magic sprouted from his shoulder, holding Blue up as if he were a mere doll. The magical claws tightened around his chest and punched out a wheeze from him.

"Shut the fuck up," Dust told him, "If you think this made me weaker, you're  _ dead wrong." _

**Author's Note:**

> my twitter is @esqers ♥


End file.
